The present invention relates to systems and methods of providing a bi-directional digital subscriber line (DSL) connection to a network, wherein a DSL modem at the customer premise connects to a DSL modem at a digital subscriber line access multiplexer (DSLAM).
xDSL services, also commonly referred to as simply DSL or digital subscriber line services, are dependent on line conditions because DSL is implemented over twisted copper pairs. Further, there are many different flavors of digital subscriber line services, each providing service over different distances, and having different bandwidths. Some implementations for DSL are asymmetric, meaning that the downstream bandwidth is different than the upstream bandwidth. Other implementations for DSL services are symmetric. xDSL technologies provide extremely high bandwidth over an embedded twisted pair, copper loop.
In existing deployments of DSL Services, the customer has a dedicated bi-directional digital subscriber line (DSL) connection from the customer premise to the central office. At the central office, the customer is connected to a network such as the Internet. A DSL modem is different than the typical analog modem. In a DSL implementation, a DSL modem at the customer""s premise receives the incoming twisted pair and connects to, for example, a home network, such as, for example, a home Ethernet network. On the central office side, the other end of the twisted pair is connected to a DSL modem at a digital subscriber line access multiplexer (DSLAM). The DSLAM includes a modem for every customer premise modem to provide a number of always-on, bi-directional, dedicated digital subscriber line connections.
That is, in existing DSL implementations, the provider must supply a DSL modem at the DSLAM for every customer DSL modem, which may quickly get expensive with increases in customer demand. For the foregoing reasons, there is a need for a method and system of providing a bi-directional digital subscriber line connection to a network that reduces cost for DSL implementation while still providing adequate service for the DSL customers.
It is, therefore, an object of the present invention to provide a system for providing a bi-directional DSL connection to a network in which switching logic has a number of inputs connected to digital subscriber lines that extend to customer premises, wherein the number of inputs is greater than a number of outputs, with the outputs being connected to a pool of provider DSL modems, allowing DSL modem pooling at the provider end.
In carrying out the above object, a system for providing a bi-directional digital subscriber line (DSL) connection to a network is provided. The system comprises a digital subscriber line access multiplexer (DSLAM) including a pool of digital subscriber line modems. The multiplexer provides communication between each modem and the network. The system further comprises switching logic. The switching logic has a number of inputs and a number of outputs. Each input is connected to a digital subscriber line that extends to a customer premise. Each output is connected to a modem in the modem pool. The number of inputs is greater than the number of outputs. The switching logic is configured to share access to the modem pool among the inputs on a per-session basis with a session having a dedicated modem connection to the network to provide a limited number of simultaneous dedicated digital subscriber line bi-directional connections to the network.
It is to be appreciated that embodiments of the present invention may be suitable for various flavors of xDSL, including rate adaptive digital subscriber line (RADSL) technology for subscriber end service delivery with asynchronous transfer mode (ATM) for host end connectivity. Of course, other flavors of xDSL may be used for subscriber end service delivery and other techniques may be used for host end connectivity. For example, the twisted pair may run from the central office, or in the alternative, fiber to the neighborhood or fiber to the curb may be used to extend the reach of the network (for example, VSDL implementations of xDSL).
In a suitable implementation, depending on customer demand, the number of switching logic inputs may be at least two times the number of switching logic outputs. Further, in some embodiments, the number of switching logic inputs may be at least three times the number of switching logic outputs. The ratio of inputs to outputs for the switching logic may be determined based on customer demand and usage patterns. Of course, the present invention is not limited to any particular inputs to outputs ratio, and some embodiments have an inputs to outputs ratio as great as six to one. Further, even greater ratios are contemplated for some embodiments of the present invention. For example, depending on customer demand and usage patterns, ratios as great as ten to one or even twelve to one for switching logic inputs to outputs may be employed.
In a preferred implementation, each simultaneous digital subscriber line connection to the network has an upstream bandwidth of at least 256 kilobytes per second. Further, in a preferred implementation, a downstream bandwidth of at least 256 kilobytes per second is provided. As such, embodiments of the present invention allow a symmetric bi-directional digital subscriber line connection of a relatively low bandwidth of 256 kilobytes per second to be provided, with modem pooling, to lower the cost to the provider and effectively lower the end cost to the customer so that more customers may enjoy the benefits of DSL service. In some embodiments, DSL is implemented asymmetrically with the downstream bandwidth being greater than the upstream bandwidth.
In a preferred implementation, the switching logic is configured with timing logic to share access to the modem pool. Preferably, the switching logic is configured with idle timer logic, session timer logic, and lockout timer logic.
The idle timer logic disconnects a connection between an input and an output of the switching logic after the expiration of a predetermined period of time with the connection remaining idle. The session timer logic disconnects a connection between the input and an output of the switching logic after the expiration of a predetermined period of time since the creation of the connection (session time limit). The lockout timer logic prevents the creation of a connection between an input and any output of the switching logic until the expiration of a predetermined period of time after disconnection of the input from any output by the session timer logic.
Further, in carrying out the present invention, a method of providing a bi-directional digital subscriber line (DSL) connection to a network is provided. A digital subscriber line access multiplexer (DSLAM) includes a pool of digital subscriber line modems. The DSLAM provides communication between each modem and the network. The method comprises configuring switching logic and sharing access to the modem pool. The switching logic is configured between the multiplexer and a plurality of customer premises. The switching logic has a number of inputs and a number of outputs. Each input is connected to a digital subscriber line that extends to a customer premise. Each output is connected to a modem in the pool. The number of inputs is greater than the number of outputs to allow modem pooling. Access to the modem pool is shared among the inputs on a per-session basis with a session having a dedicated modem connection to the network to provide a limited number of simultaneous dedicated digital subscriber line bi-directional connections to the network.
In some implementations, depending on customer demand, the number of switching logic inputs may be at least two times the number of switching logic outputs. Further, the number of switching logic input may be at least three times the number of switching logic outputs. Of course, the present invention is not limited to any particular inputs to outputs ratio, and some embodiments have an inputs to outputs ratio as great as six to one. Further, even greater ratios are contemplated for some embodiments of the present invention. For example, depending on customer demand and usage patterns, ratios as great as ten to one or even twelve to one for switching logic inputs to outputs may be employed.
Preferred embodiments for the invention further comprise configuring the switching logic to share access to the modem pool by, upon receiving a connection request from a customer premise at an input when each output is already in use by a dedicated connection to the network from a different input, sending a message to the customer premise indicating that all modems are currently in use. Preferably, the invention further comprises configuring the switching logic to share access to the modem pool by, upon receiving a connection request from a customer premise at an input when an output is available for use, establishing a digital subscriber line connection to the network including a connection between the requesting input and any available output. Still further, in a preferred embodiment, the method further comprises configuring the switching logic with idle timer logic, session timer logic, and lockout timer logic.
The advantages associated with the embodiments of the present invention are numerous. For example, systems and methods of the present invention provide DSL modem pooling at a provider central office or a remote DSLAM for FTTx configurations. Embodiments of the present invention allow the provider to, based on customer demand and usage patterns, oversubscribe services and resultantly reduce the cost of the network allowing DSL to reach more people, faster, and cheaper. It is to be appreciated that the switching logic inputs to outputs ratio (the amount of over subscription) may vary in different implementations of the present invention. For example, an input to output ratio may be two to one (2 to 1), three to one (3 to 1), six to one (6 to 1), ten to one (10 to 1), twelve to one (12 to 1), or any other ratio as deemed appropriate for the particular DSL implementations.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.